Vapor electric lamp.



H. I. WOOD.

VAPOR ELECTRIC LAMP.

APPLIOATIoN FILED un. za. 1904.

1,006,421 Patented Oct. 17, 1911.

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UNITED sTATEs PATENT OFFICE.

HOWARD I. WOOD, OF SCHENECTADY, NEW YORK SSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

VAPOR ELECTRIC LAMP.

Specification of Letters Patent.'

Patente-a oct. 17, 1911.

Original application led february 14, 1903, Serial No. 143,329. Divided vami this application tiled January 28, 1904. Serial No. 190,293.

To all whom it mag/concern:

Be it known that I, HOWARD I. lvoon, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Vapor Electric Lamps, (divislon of my pending applica.-4 tion, Serial No. 143,329, fi ed February 14, 1903,) of which the following is a specification.

My invention relates to that type of electric lamp in which electricity passes through a vapor contained within an exhausted envelop, and comprises a certain method of starting a lamp of the character mentioned, the novel features Vof which I have pointed out with particularity in the claims appended hereto.

'For a detailed description of my invention, reference is to be had to the following specification taken in connection with the accompanying drawings in which- Figures 1, 2 and 3 represent by way of illustration some of the various forms which my invention may assume in practice.

As shown in F-ig. l the envelop of the lamp is a straight glass tube l, of suitable length, though it is to be understood that the size, shape, length, or other dimensions of the envelop may be widely varied wit-hout departing from my invention.k At the bottom of the tube is contained a body of mercury 2 forming one of the electrodes with which connection is made by the leading-in conductor 3. The upper terminal of the lamp consists of a cylindrical stick of artificial graphite 4 or if desired this may be replaced by a cylindrical shell of steel or other suitable material, or indeed both electrodes may be of mercury or other suitable.-

vaporizable substance. This electrode 4 is supported by a wire 5 of some length, the upper end of which serves as a leading-in conductor, passing through the walls of the tube as indicated at 6,-the outer end forming the lamp terminal 7. The conductor 5 is surrounded by a glass tube 8 depending Jfrom-the upper wall of the glass envelop 1 and extending down to the electrode 4. this tube 8 prevents the electric discharge within the envelop l from extending above the electrode 4, and also serves as a mechanical means for preventing lateral dis* placement of the electrode. Electrically connected to the electrode 4 and extending down therefrom is a filament 9 of carbon or other suitable material, which passes very loosely through a guide or su porting ring or loop 10. The lower end o this filament 9 dips lightly into the surface of .the mercury electrode 2, thereby making what may be termed a poor contact, or a contact ppssessing high transition resistance.

rhen now, the lamp, highly exhausted, is connected with a source of electric current, current flows through the lamp by the circuit aiforded by the electrodes 2 and 4 which are electrically connected by the filament 9. The contact between the lower end of the filament and the mercury 2 however is such that the current, in passing between the filament and the mercury, flows through". a comparatively small volume of mercury. By reason of this How of current ionized mercury vapor is produced, the eiiect of which is to cause an electric arc or discharge to flash into ex# istence between the main electrodes 2 and 4, completely filling the tube. The rst incipient arc or discharge takes place between the mercury and the lower end of the filament 9, and extends instantly upward along the filament until it reaches the electrode 4, the action however being too rapid for the eye to follow. The arc or electric discharge which then fills the tube affords a path :for the current, of much better conductivity than that presented by the filament 9, so that current practically ceases to flow in the filament, as evidenced by the fact that the filament remains black. It is possible that minute arcs are generated between the mercury 2 and the portion of the filament 9 engaged thereby, though according to my present understanding of the action it seems more probable that the initial disengagement of ionized vapor is due to heat developed by the current {iowing through the relatively high resistance contact between the lower end of the filament and the mercury.

Instead of arranging l the lamp in the vertical position shown in Fig. 1,`it may, if

desired, be arranged so as to run in a position slightly inclined from the horizontal as indicated in Fig. 2 in which the lamp is of substantially the same construction as shown in Fig. 1 except that the lowerelectrode consists of a body of .mercury 11 contained ina slight downward extension4 12 of the tube 13. The filament 14 is supported by a guide or guides such as so that its free end rests lightly on or projects slightly into the surface of the mercury 1 1 :xs-indicated at 16.'- The operation of the lamp is substantially that described in connectionv with In both the arrangements shown in Figs. 1 and 2 the filament.J makes a sort of yielding engagement with the surface of the mercury so that slight changes in the level of the mercury caused by more or less condensed* mercury accumulating inportions of the tube during operation do not interfere with the operativel starting. relation between the filament and the mercury electrode. In-

. a vstead of 'providing a: yielding' engagement between the iilament. and the mercury electrode, afforded by the 4 ielding filament, "as

to accommodate itselfto 'variations in the level o f the mercury electrode 20.

Ther-starting means which I have `above described will operate when alternating curl rent is `supplied to the lamp, though I ind that the operation is much more satisfactory .with direct current, sincewith alternating current a disintegration ofthe lower end of the filament takes place, thus blackening the walls of the tube, which action does not take placeto .the slightes'textent with direct. eur.l

rent.

I am thus enabledto. which is started4 on thevoltage and characterof currentA on whichit runs, by merelyi vclosing theswitch.

What I claim as new and desireftosecure -by Letters Patent of the United states, is,

1. The method of starting al vapor electric device having an exhausted envelop `provided with electrodes, one at least ofysaid .electrodes being of -vaporizable material,

which consists in causing the initial ilow of culrrent to enter said -vaporizable material through a; poor or relatively high resistance contact, so tof generate ionized vapor at said contact, thereby causing the main dis- A charge to .take place between said electr-odes.

2; The method of initiating an electric discharge between electrodes within an -exhausted envelop, one at least of which electrodes is of vaporizable material, which consists in first causing current to flow through a localized portion of the surface layer of the vaporizable electrode and bv the. local acsists in initially causing current to iiow through the envelop in a normally conducting'path, the resistance df which at the surface of one of the electrodes is suliicient to cause the. generation of heat, and therefore the disengagement of conducting vapor.

'- 4.v The method of starting a vapor electric `ap `aratus having an exhausted envelop prolvi ed with electrodes, one at least of said electrodes being of vaporizable material, which consists path including said vaporizable electrode,

' and concentrating the heating energy of said current on a relatively small volume of said -vaporizable material located in a predeter- .mined position so as to disengage vapor and subsequently develop an are.

5.. The method of starting a vapor electric apparatus having an exhausted envelop. provided with electrodes,

in passing current through a one at least of said electrodes vbeing of vaporizable material,

which consists in passing c'urrent through a conductor of small cross-section making a transition resistance, said current being su produce a lamp` cient in quantity to disengage ionized vapor om said vaporizable electrode at said contact by the local actionfof said current,

. 95 light, surface contact with relatively small thereby rendering said evacuated envelop electrode. f .7. The method of starting'avapor electric apparatus having an exhausted envelop provided with=electrodes, one at least of said electrodes being of vaporizable material, which consistsv in' passing current through a conductor whichA contacts at one end with onlya small quantity of the surface layer of said vaporizable. material, 'said' current being suiiicient in quantity to effect localized heating near said contacting end and the disengagement of ionized vapor from said vaporizable electrode near the end of said conductor, thereby starting an arc in said exhausted envelop.

8. The method of starting a vapor electric apparatus having an exhausted envelop pro-4 -cOnductivefor' an arc'from said vaporizable Aelectrodes being of vaporizable material,

" which consists in passing current to Vsaid vaorizable' electrode through a.' conductor of imited cross sectional area, the point of contact having a, higher resistance than said conductor,` so as to localize' the `heating nc-v tion of said current and thereby start said apparatus.

9. The method of starting u vapor electric.' a paratus havlngan exhausted envelop" prol vlded with electrodes, one :it least of saidelectrodes being of 'ivaporizable material; V-

which consists in passingn'curr'ent through La;

conductor contacting with the surfnceof said vuporiznble electrode find by the action of said current -nt the end only of Suid conductor initiating nn are in' said envelop while said conductor' remains stationary with -respect'to the mein-.body of said vaporzoA 

